The overall objective of the 5th Annual X Chromosome Workshop is to gather together investigators from laboratories which are most active in the study of the human and mouse X chromosomes, in order to exchange mapping data, assemble up-to-date working maps, and promote the sharing of materials. The 5th Annual workshop will be held at the DKFZ Communication Center in Heidelberg, Germany, on April 24-27, 1994. The workshop is by invitation only with an anticipated 80-85 participants.